1. Field of the Invention
The present invention relates to a magnetic head slider, which flies above a magnetic recording medium with a minute spacing therebetween, for writing and reading magnetic information. More particularly, the invention relates to a magnetic head slider in which adhesion of the surface of a slider body facing a recording medium on the side of a magnetic disk to the magnetic disk can be further decreased without adversely affecting the flying.
2. Description of the Related Art
A conventional magnetic disk unit as shown in FIG. 10 is known for magnetic recording apparatuses for computers.
In this magnetic disk unit, a magnetic head slider 82 is disposed opposite to a magnetic disk 81 which is rotatably provided, and the magnetic head slider 82 is supported by an arm 84 with a triangular leaf spring 83 therebetween. The magnetic head slider 82 can be moved to a predetermined position in the diametric direction of the magnetic disk 81 due to the rotation of the arm 84 around a rotation center 84a. 
In the magnetic disk unit having the structure shown in FIG. 10, when the magnetic disk 81 is stopped, the bottom surface of the magnetic head slider 82 is gently pressed to the magnetic disk 81 by the elastic force of the leaf spring 83 which supports the magnetic head slider 82. When the magnetic disk 81 is rotated, the magnetic head slider 82 flies above the magnetic disk 81 at a predetermined height using the airflow caused by the rotation. When the rotation of the magnetic disk 81 is stopped, the magnetic head slider 82, which has been flying, comes into contact with the magnetic disk 81 again and stops. Magnetic information is read and written from and into a magnetic recording layer of the magnetic disk 81 while the magnetic head slider 82 is flying. Such a series of operations are usually referred to as CSS (Contact-Start-Stop) operations.
FIG. 11 shows the flying state of a 2-rail type magnetic head slider 82, which is widely used. On the bottom surface of the magnetic head slider 82, a groove (not shown in the drawing) is formed in the center, and side-rails 86 are formed on both sides with the groove therebetween. An inclined area 86a is formed on the lower surface of the tip of each side-rail 86. As the air inflow occurs through the inclined area 86a as indicated by arrows A in FIG. 11, the bottom surface of the side-rail 86 of the magnetic head slider 82 acts as a positive pressure-generating section so that the magnetic head slider 82 flies. In each side-rail 86, the width of the magnetic head slider 82 on the front side (the air inflow side 82a) is set to be broader than the width on the rear side (the air outflow side 82b).
A structure of a magnetic head slider is also known in which, as shown by the double-dotted chain line in FIG. 11, a negative pressure groove 86b is formed in the bottom surface of the side-rail 86, and by balancing negative pressure generated by the negative pressure groove 86b and positive pressure generated by the side-rails 86, flying performance is stabilized.
When the magnetic head slider 82 flies, air flows toward the bottom side of the magnetic head slider 82 through the inclined area 86a, and in the case in which the negative pressure groove 86b is further formed, since negative pressure is generated at the rear of the magnetic head, the magnetic head slider 82 flies while tilting at a very small angle with the air inflow side 82a being lifted. Generally, this angle of tilt is referred to as the pitch angle (xcex1: usually, approximately 100 xcexcRad).
In the magnetic head slider 82 having the structure as described above, the slider 82 comes into sliding contact with the magnetic disk during starting and during stopping of the magnetic disk 81. Therefore, in order to avoid abrasion and wear on the surface of the magnetic disk, a protective film may be formed on a recording layer of the magnetic disk 81, and a lubricating layer may further be formed on the protective film.
In the magnetic head slider 82 having the structure described above, in view of magnetic recording, since it is advantageous to bring a magnetic gap G of the magnetic head slider 82 as close to the magnetic recording layer of the magnetic disk 81 as possible, the flying height of the magnetic head slider 82 is preferably decreased as much as possible. As the recording densities of the magnetic disk units are increased and magnetic disk units are miniaturized, there are trends to further decrease the flying height (the amount of space between the magnetic head slider 82 and the magnetic disk 81) of the magnetic head slider 82. When the flying height is decreased, the surface roughness of the magnetic disk 81 must be decreased as much as possible in order to avoid contact between the magnetic disk 81 and the magnetic head slider 82 in the flying state. However, during starting or during stopping of the magnetic disk 81, the smoother the surface of the magnetic disk 81, the greater the contact area between the magnetic disk 81 and the magnetic head slider 82, and the slider 82 easily adheres to the magnetic disk 81, thus increasing adhesion torque.
If the adhesion torque is increased, the load during the starting of the motor for rotating the magnetic disk 81 is increased, and a magnetic head element provided on the arm 84 or the slider 82 and the recording layer of the magnetic disk are easily damaged when the magnetic disk 81 starts rotating.
In order to solve such problems, a magnetic head slider was proposed in which, as shown in FIG. 12, by forming a crown on the surface of a magnetic head slider 82 facing a recording medium on the side of a magnetic disk 81, and also by forming a crown on each side-rail 86, the contact area between the magnetic head slider 82 and the magnetic disk 81 is decreased. A magnetic head slider was also proposed in which, as shown in FIG. 13, protrusions 89a and 89b are provided on each side-rail 86 of a magnetic head slider 82 in the longitudinal direction of the side-rail 86, and thus the contact area between the magnetic head slider 82 and the magnetic disk 81 is decreased. Additionally, FIGS. 12 and 13 are side views which show the flying states of the individual magnetic head sliders.
In the magnetic head slider, as described above, because of the demands for increasing the recording density of the magnetic disk unit and for miniaturizing the magnetic disk unit, the flying height of the magnetic head slider 82 tends to be decreased, and the pitch angle is accordingly also decreased.
However, in the conventional magnetic head slider provided with the crown as shown in FIG. 12, if the recording density is increased and the flying height is decreased, the flatness of the magnetic recording medium is increased and the magnetic head slider easily adheres to the magnetic recording medium, and thus the effects anticipated from the provision of the crown are not easily obtained, depending on the pattern of the surface facing the recording medium, i.e., the shape and width of each side-rail 86, and the shape and width of the groove between the side-rails 86.
In the conventional magnetic head slider provided with the protrusions 89a and 89b as shown in FIG. 13, if the pitch angle is decreased, in the flying state, the protrusion 89b near the air outflow side 82b protrudes toward the magnetic disk 81 more than the magnetic gap G, and thus it is not possible to decrease the flying height.
Consequently, it may be envisioned that the position of the protrusion 89b should be shifted from near the air outflow side 82b to the air inflow side 82a by a length L1, as indicated by the broken line in FIG. 13. However, when the pitch angle is small, the position of the protrusion 89b must be shifted to the air inflow side 82a by a considerable amount, and even in such a case, the area in which a portion of the surface of the magnetic head slider 82 facing the recording medium (the surface facing the recording medium in the vicinity of the magnetic gap G), which is not provided with a protrusion, is brought into contact with the magnetic disk 81 is increased when the magnetic disk 81 is stopped, and thus the surface of the magnetic head slider 82 facing the recording medium easily adheres to the magnetic disk 81.
Accordingly, it is an object of the present invention to further decrease adhesion of the surface facing a magnetic disk of a slider body to the magnetic disk without adversely affecting the flying performance.
In accordance with the present invention, a magnetic head slider, which writes or reads magnetic information while flying above a magnetic disk, includes a slider body provided with a magnetic head core; and a rail and/or a pad for generating lift, provided on the surface facing a recording medium of the slider body. A crown is formed at least at a position on the rail selected from the group consisting of the surface facing the recording medium of the slider body, the rail, and the pad. The rail is provided with side-rails formed on both sides of the surface facing the recording medium of the slider body and extending from the air inflow side to the air outflow side of the slider body. A groove is provided between the side-rails, and at least one protrusion is provided on each side-rail on the air inflow side and/or on each side of the groove on the air inflow side. The protrusion protrudes more toward the magnetic disk than the side-rails.
In the magnetic head slider having the structure described above, since the crown is formed at least at a position on the rail selected from the group consisting of the surface facing the recording medium of the slider body, the rail, and the pad, the contact state between the portions of the side-rails on the air outflow side (portions of the side-rails in the vicinity of the magnetic gap of the magnetic head core) and the magnetic disk can be linear instead of being planar, and thus the contact area between the slider body and the magnetic disk can be reduced, and the effect of decreasing adhesion between the slider body and the magnetic disk can be improved.
By forming the crown on the rail as described above, it is possible, during flying, to bring the magnetic gap of the magnetic head core closer to the magnetic disk in comparison with the other sections. That is, the flying height of the magnetic gap can be set to be the smallest, which is advantageous. Since the side-rails on the air outflow side are not provided with a protrusion, there are no adverse effects on flying.
Since at least one protrusion is provided on each side-rail on the air inflow side and/or on each side of the groove on the air inflow side, and since the protrusion protrudes more toward the magnetic disk than the side-rails, portions of the side-rails on the air inflow side are not in contact with the magnetic disk and the protrusion comes into contact with the magnetic disk. Thus, the effect of decreasing adhesion between the slider body and the magnetic disk can be improved in comparison with a case in which no protrusion is provided. That is, unless at least one protrusion is provided on each side-rail on the air inflow side and/or on each side of the groove on the air inflow side, even if the contact state between the portions of the side-rails on the air inflow side and the magnetic disk is linear, since the contact line is long, adhesion easily occurs. However, if at least one protrusion is provided on each side-rail on the air inflow side and/or on each side of the groove on the air inflow side, the contact state between the protrusion and the magnetic disk can be a point or can be a short line, and thus the effect of decreasing adhesion between the slider body and the magnetic disk is increased.
Since at least one protrusion is provided on each side-rail on the air inflow side and/or on each side of the groove on the air inflow side, at least one protrusion is provided on the slider body on the air inflow side and on each side in the width direction, and thus it is possible to prevent any side in the width direction (lateral direction) of the slider body from tilting and coming into contact with the magnetic disk, and sufficient flying stability can be obtained.
Consequently, in accordance with the magnetic head slider of the present invention, it is possible to provide a magnetic head slider having superior characteristics in which the effect of decreasing adhesion between the slider body and the magnetic disk can be maximized by reducing the contact area between the air inflow side (leading side) of the magnetic head slider and the magnetic disk, and the contact area between the air outflow side (trailing side) and the magnetic disk, during flying, and also flying is not adversely affected.
In the magnetic head slider of the present invention having the structure described above, the rail may be provided with side-rails formed on both sides of the surface facing the recording medium of the slider body and extending from the air inflow side to the air outflow side, and a center rail and/or a pad formed between both side-rails.
In the magnetic head slider of the present invention, preferably, the width of the side-rail on the air inflow side is broader than the width of the side-rail on air the outflow side. The flying attitude can thereby be more satisfactorily maintained.
In the magnetic head slider of the present invention having any one of the structures described above, preferably, a cutout section, which forms a discontinuous surface on the crown, is provided on each side-rail. Consequently, when the magnetic head slider is mounted on an arm with a leaf spring therebetween, the spring pressure sensitivity can be decreased, and also a variation in the distribution of flying heights of the magnetic head slider from the center to the peripheral side can be minimized, and thus a satisfactory constant flying height (CFH) can be obtained.
When the cutout section as described above is provided on the side-rail, the protrusion is preferably provided on the side-rail at a position close to the cutout section in order to improve flying characteristics.
In the magnetic head slider of the present invention having any one of the structures described above, preferably, the height of the protrusion is greater than the crown height. Herein, the height of the protrusion corresponds to a distance from the surface of the side-rail to the apex of the protrusion when the protrusion is provided on the side-rail which is not provided with the cutout section; corresponds to a distance from the bottom surface of the cutout section to the apex of the protrusion when the protrusion is provided on the side-rail provided with the cutout section; and corresponds to a distance from the bottom surface of the groove to the apex of the protrusion when the protrusion is provided in the groove. The crown height corresponds to a distance between a line that links both ends in the longitudinal direction of the surface of the slider body facing the recording medium to each other and the highest position of the crown; or corresponds to a distance between a line that links the starting point to the ending point of the side-rail and the highest position of the crown.
The upper limit of the height of the protrusion is the sum of the flying height of the slider body and an increment in pitch (distance from the magnetic gapxc3x97pitch angle).
In the magnetic head slider of the present invention having any one of the structures described above, when the magnetic head slider is flying, preferably, the protrusion protrudes less toward the magnetic disk than the magnetic gap.
In such a magnetic head slider, when the magnetic head slider is flying, the protrusion does not have the smallest flying height. That is, the magnetic gap could be brought closer to the magnetic disk in comparison with the protrusion.
In the magnetic head slider of the present invention having any one of the structures described above, preferably, the protrusion is not provided on the surface of the slider body facing the recording medium in the region in which the distance from the magnetic gap is one-third or less of the length of the slider body. Consequently, it is possible to prevent the protrusion from being closer to the magnetic disk than the magnetic gap during flying of the magnetic head slider.
In the magnetic head slider of the present invention having any one of the structures described above, preferably, the protrusion is composed of a carbon film having a film hardness of 22 GPa or more.
In such a magnetic head slider, by setting the hardness of the protrusion to a film hardness of 22 GPa or more, the abrasion resistance of the protrusion can be significantly improved, and even if the protrusion is brought into sliding contact with the magnetic disk during starting and during stopping, abrasion does not easily occur. Thus, it is possible to prevent the contact area between the slider body and the magnetic disk from increasing, and an increase in adhesion between the slider body and the magnetic disk can be avoided.
In the magnetic head slider of the present invention having any one of the structures described above, preferably, a first carbon film having corrosion resistance is provided, with a bonding layer therebetween, at least at a position on the rail selected from the group consisting of the surface facing the recording medium of the slider body, the rail, and the pad; the protrusion is provided on the first carbon film; the protrusion includes at least one intermediate film and at least one second carbon film alternately formed; and at least the outermost second carbon film has abrasion resistance.
In such a magnetic head slider, since the second carbon film having abrasion resistance is formed on the outermost surface of the protrusion, even if the protrusion is brought into sliding contact with the magnetic disk during starting and during stopping, abrasion does not easily occur, and thus the abrasion resistance of the protrusion can be significantly improved. Furthermore, since the surface of at least the rail selected from the group consisting of the surface of the slider body facing the recording medium, the rail, and the pad is covered by the first carbon film having corrosion resistance, it is possible to prevent the magnetic head core provided on the slider body from deteriorating due to corrosion.
As described above, since the abrasion resistance of the protrusion is significantly improved, it is possible to prevent the contact area between the slider body and the magnetic disk from increasing, and it is also possible to prevent a magnetic head element provided with the magnetic head core, a recording layer of the magnetic disk, etc., from being damaged due to increased adhesion between the slider body and the magnetic disk when the magnetic disk starts rotating.
When the first carbon film and the second carbon film having the characteristics described above are formed by electron cyclotron resonance chemical vapor deposition (ECRCVD), carbon films having different characteristics can be efficiently produced by changing the types of reactant gas (gas containing carbon) to be fed into a deposition system, and by adjusting the substrate bias.
In the magnetic head slider of the present invention having any one of the structures described above, preferably, the first carbon film having corrosion resistance is a carbon film with a hydrogen content of 30 atomic % or more, and the second carbon film having abrasion resistance is a carbon film having a film hardness of 22 GPa or more.
The first carbon film having the hydrogen content of 30 atomic % or more can be deposited, for example, by changing the types of reactant gas (gas containing carbon) to be fed into a deposition system and by adjusting the substrate bias (decreasing the substrate bias) when the first carbon film is formed on the slider body provided with a bonding layer using ECRCVD. By using methane gas as the reactant gas, a carbon film with a hydrogen content of 35 atomic % or more can be deposited. When ethylene gas is used as the reactant gas, it is possible to deposit a carbon film having a hydrogen content of more than 30 atomic % by the substrate bias.
By increasing the hydrogen content in the first carbon film covering the surface of at least the rail selected from the group consisting of the surface of the slider body facing the recording medium, the rail, and the pad as described above, although the film hardness is decreased, density is increased because the carbon becomes amorphous, and adhesion is increased, and thus detachment does not easily occur. Therefore, it is possible to prevent the magnetic head core provided on the slider body from deteriorating due to corrosion.
The second carbon film having a hardness of 22 GPa or more can be deposited by decreasing the hydrogen content in the carbon film, for example, by changing the types of reactant gas (gas containing carbon) to be fed into a deposition system and by adjusting the substrate bias (increasing the substrate bias) when the second carbon film is formed on an intermediate film of the slider body provided with the a bonding layer, a first carbon film, and the intermediate film.
The hydrogen content in the second carbon film is preferably set at less than 30 atomic %.
As described above, by decreasing the hydrogen content in the second carbon film constituting the protrusion, bonds between carbon atoms are strengthened, and thus the hardness can be increased.
The second carbon film may be a carbon film having a hydrogen content of 0 atomic %. Examples of such a carbon film include a film formed of cathodic-arc carbon (CAC). A second carbon film composed of cathodic-arc carbon can be deposited, for example, by placing a slider body provided with a bonding layer, a first carbon film, and an intermediate film in a deposition system, and then subjecting a lump of graphite to arc discharge in a vacuum.
Furthermore, in the magnetic head slider of the present invention having any one of the structures described above, preferably, the magnetic head core is provided with a giant magnetoresistive element.